Senior woman organizing weekly medicationShare on Pinterest
Willie B. Thomas/Getty Images

AFib and blood thinners

Atrial fibrillation (AFib) is a heart rhythm disorder that may increase your risk of stroke. With AFib, the upper two chambers of your heart beat irregularly. Blood may pool and collect, creating clots that can travel to your organs and your brain.

Doctors often prescribe anticoagulants to thin the blood and prevent clots from forming.

Here’s what you need to know about long-term blood thinner use, any side effects you might experience, and what you may want to discuss with your doctor.

Anticoagulants may lower your stroke risk by up to 50 to 60 percent. Because AFib doesn’t have many symptoms, some people feel they don’t want or need to take blood thinners, especially if it means taking a drug for the rest of their lives.

While blood thinners don’t necessarily change how you feel on a day-to-day basis, they’re extremely important to protect yourself against stroke.

You may encounter several types of blood thinners as part of treatment for AFib. Warfarin (Coumadin) has been the traditionally prescribed blood thinner. It works by reducing your body’s ability to make vitamin K. Without vitamin K, your liver has trouble making blood-clotting proteins.

However, new, shorter-acting blood thinners known as non-vitamin K oral anticoagulants (NOACs) are now recommended over warfarin for people with AFib, unless the person has moderate to severe mitral stenosis or an artificial heart valve. These medications include dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa).

Some people shouldn’t take blood thinners. Be sure to tell your doctor if you have any of the following medical conditions in addition to AFib:

  • uncontrolled high blood pressure
  • stomach ulcers or other issues that put you at high risk for internal bleeding
  • hemophilia or other bleeding disorders

One of the most obvious side effects of blood-thinning medication is the increased risk of bleeding. You may even be at danger of bleeding significantly from small cuts.

Be sure to tell your doctor if you experience a long nosebleed or bleeding gums, or see blood in your vomit or feces. Severe bruising is something else you may see that needs a doctor’s attention.

Along with bleeding, you may experience skin rashes and hair loss as side effects while on the drug.


If you’re taking warfarin for the long haul, you’ll likely be monitored closely by your medical team.

You may regularly visit the hospital or clinic to have a blood test called prothrombin time. This measures how long it takes for your blood to clot. It’s often performed monthly until your doctor can figure out a proper dose that works for your body.

Having your blood checked is something you’ll likely need to do while you’re taking the drug. Some people don’t need to change their dosage of medication very often. Others must have frequent blood tests and changes to their dosage to avoid side effects and excess bleeding.

You may also need to be checked before having certain medical procedures that involve bleeding, like surgery.

You may notice that the color of your warfarin pill is different from time to time. The color represents the dosage, so you should keep an eye on it and ask your doctor if you have questions about seeing a different color in your bottle.


Shorter-acting blood thinners like novel oral anticoagulants (NOACs) don’t usually require frequent monitoring. Your doctor can give you more guidelines for treatment and any changes in dosage.


Warfarin may interact with different medications you’re taking. The foods you eat may also interfere with its effect on your body. If you’re taking this drug for a long period of time, you’ll want to ask your doctor more about your diet — especially about foods high in vitamin K.

These foods include green, leafy vegetables:

  • kale
  • collard greens
  • Swiss chard
  • mustard greens
  • turnip greens
  • parsley
  • spinach
  • endive

You should also talk to your doctor about any herbal or omega-3 supplements you’re taking to see how they may interact with blood thinners.


NOACs don’t have any known food or drug interactions. Speak with your doctor to see if you’re a candidate for taking these medications.

If you have concerns about taking blood thinners long-term, speak with your doctor.

It’s important that you take your medication at the same time each day. If you miss a dose, call your doctor to see how you should get back on track.

Some who remember their missed dose close to when they normally take it may be able to take it a few hours late. Others may need to wait until the following day and double up their dose. Your doctor can advise you on the best method for your situation.

Call 911 immediately if you experience any of the following symptoms while on blood thinners:

  • a severe or unusual headache
  • confusion, weakness, or numbness
  • bleeding that won’t stop
  • vomiting blood or blood in your stool
  • a fall or injury to your head

These situations may be signs of either internal bleeding or could lead to extreme blood loss. Acting fast may save your life.

There are antidote medications that can stop the effects of warfarin and get your blood to clot in an emergency, but you’ll need to go to a hospital for treatment.

Bleeding is the biggest risk with long-term blood thinner use. If you’re on the fence about taking them for this reason, consider making a few lifestyle changes. The following are things you can do at home to reduce your chances of bleeding from everyday activities:

  • Toss any firm-bristle toothbrushes, and switch to ones with soft bristles.
  • Use waxed floss instead of unwaxed, which may damage your gums.
  • Try an electric razor to avoid nicks and cuts.
  • Use sharp objects, like scissors or knives, with care.
  • Ask your doctor about participating in any activities that might increase your chance of falling or injury, like contact sports. These may also increase your risk of internal bleeding.

If you’re taking warfarin, you may also want to limit certain foods from your diet that might interact with the medication. Instead, try eating a variety of foods that are low in vitamin K, including:

  • carrots
  • cauliflower
  • cucumbers
  • peppers
  • potatoes
  • squash
  • tomatoes

Remember that blood thinners may not make you feel better on a daily basis. Still, they’re one of the best measures you can take to protect yourself against stroke. If you have concerns about blood thinners and long-term use, speak with your doctor about the risks versus benefits.